Expression of estrogen receptor GPR30 in the rat spinal cord and in autonomic and sensory ganglia

Abstract

The G protein–coupled receptor GPR30 has recently been identified as a nonnuclear estrogen receptor. Reverse transcriptase–polymerase chain reaction revealed expression of GPR30 mRNA in varying quantities in the rat spinal cord, dorsal root ganglia, nodose ganglia, trigeminal ganglia, hippocampus, brain stem, and hypothalamus. Immunohistochemical studies that used a rabbit polyclonal antiserum against the human GPR30 C‐terminus revealed a fine network of GPR30‐immunoreactive (irGPR30) cell processes in the superficial layers of the spinal cord; some of which extended into deeper laminae. A population of neurons in the dorsal horn and ventral horn were irGPR30. Dorsal root, nodose, and trigeminal ganglionic neurons displayed varying intensities of irGPR30. Positively labeled neurons were detected in the major pelvic ganglion, but not in the superior cervical ganglion. A population of chromaffin cells in the adrenal medulla was irGPR30, so were cells of the zona glomerulosa. Double‐labeling the adrenal medulla with GPR30 antiserum and tyrosine hydroxylase antibody or phenylethanolamine‐N‐methyltransferase antiserum revealed that irGPR30 is expressed in the majority of tyrosine hydroxylase–positive chromaffin cells. Last, some of the myenteric ganglion cells were irGPR30. Tissues processed with preimmune serum resulted in no staining. Voltage‐sensitive dye imaging studies showed that the selective GPR30 agonist G‐1 (1, 10, and 100 nM) depolarized cultured spinal neurons in a concentration‐dependent manner. Collectively, our result provides the first evidence that GPR30 is expressed in neurons of the dorsal and ventral horn as well as in sensory and autonomic neurons, and activation of GPR30 by the selective agonist G‐1 depolarizes cultured spinal neurons.